Since the US anthrax attacks in 2001, many governments have stepped up their efforts to develop new defence measures against the potential threat of bioterrorism and the use of biological weapons. In this issue, Burnett et al. review the current status and future challenges in developing detection methods and diagnostic tools and treatments against biological weapons. A threat of another kind currently faced by many people is that of cancer. A well-established weapon against cancer is chemotherapy, many forms of which use platinum-based drugs. Wang and Lippard provide an overview of the recently discovered cellular pathways that are activated in response to the platinum-based drug cisplatin, which could provide important insights for the development of more efficient therapeutic strategies. Osteoarthritis is another highly prevalent disorder, but one that has received considerably less attention than other rarer diseases. Wieland et al. argue that osteoarthritis needs to be considered as a systemic disorder to address the challenges of identifying novel therapeutics and establishing a pathophysiologically validated animal model to aid future developments in this field. In the fourth in our series of articles on model organisms, Jones et al. highlight the importance of the nematode worm Caenorhabditis elegans in identifying potential drug targets that selectively control nematode parasites, and in understanding the factors underlying many human diseases. In an 'Innovation' Perspective, Stoughton and Friend discuss the benefits of molecular profiling, including lower failure rates at all stages of the drug development process, faster progression from discovery to clinical trials and more effective and safe therapies. Finally, as Frokjaer and Otzen discuss, the increasing use of recombinant DNA technology has created a rise in the number of approved biotechnology medicines, such as therapeutic proteins, the successful formulation of which depends on a detailed understanding of their physico-chemical and biological characteristics.